|Publication number||US5680993 A|
|Application number||US 08/464,952|
|Publication date||Oct 28, 1997|
|Filing date||Jun 5, 1995|
|Priority date||Jun 5, 1995|
|Also published as||CA2223444A1, CA2223444C, EP0830214A1, WO1996039258A1|
|Publication number||08464952, 464952, US 5680993 A, US 5680993A, US-A-5680993, US5680993 A, US5680993A|
|Inventors||Thomas W. McCracken, Kevin A. Jonasson, Adam J. Bennett|
|Original Assignee||National Research Council Of Canada|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (19), Referenced by (20), Classifications (13), Legal Events (12)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to nozzles in general and in particular to atomizing nozzles utilized in agricultural spray equipment.
It is common to spray a variety of liquid chemicals on field grown crops in order to enhance the growth thereof or to inhibit destruction of the crops by insects or other pests. With some types of chemical fertilizers or pesticides it is desirable to carry the spray to the underside of the plant leaves for optimum effectiveness. When spraying the liquid onto the plants it is well known to utilize air shear spraying equipment which involves a long hollow boom which is connected to a source of air under pressure, the boom being provided with a series of spaced apart nozzles therein. Each nozzle is supplied with liquid under pressure, which liquid is mixed with air from the boom so that the liquid is atomized at the exit from the nozzle. The pressurized air from the boom carries the liquid as a cone-shaped spray towards the plant. Additional nozzles at the exit from the nozzle have been used to shape the cone-shaped spray into a more fan-shaped configuration.
Present agricultural spray technology does not provide an optimized application of liquid, whether herbicide or pesticide, with an air shear device which is characterized by a controlled droplet size distribution and a well-defined liquid patternation. Droplet size is an issue in that too fine a spray will result in off-target drift and too coarse a spray will result in poor spray efficacy. In order to maximize target contact the atomizer must have an even velocity profile.
An air shear spray device is disclosed in U.S. Pat. No. 4,504,014. The system of that patent has demonstrated the benefits of improved spray delivery by significantly increasing weed and pest control. The atomizer design of that patent, however, limits any decrease in chemical usage, or improvement in operational range and spray efficacy. Simultaneous control of droplet size distribution and spray pattern over the desired operational range is not achieved with the design of that patent.
The hydraulic sprays generated by traditional fan jet equipment produce spray characterised by large droplets with relatively slow delivery velocities and thus require significantly larger application rates to effect the same crop control as contact with the target plants is not efficient. Air assisted spray systems that make use of controlled air delivery to accelerate the liquid spray to the target leaf canopy are also limited by the performance of hydraulic nozzles. Air shear systems are limited in performance by the atomization mechanism associated with inconsistent liquid filming and poor control of the aerodynamic shear environment associated with the droplet breakup mechanism.
There is therefore a need for a better atomizer for agricultural spray systems which will provide a controlled or limited droplet size distribution to avoid poor efficacy due to droplets that are too large, or drifting or off-target delivery due to droplets that are too small.
The present invention overcomes the problems associated with the prior art agricultural spray systems by providing an atomizing nozzle that has a narrow and controlled droplet size distribution and the ability to shape the spray into a solid cone or fan that can evenly apply the spray to the crops. The nozzle of the present invention is able to operate at low air delivery pressures, in the order of 10 to 30 in. of water column. The simple design has a central air delivery bore or throat communicating with an air manifold within the boom. Near the exit plane of the bore there is provided an inlet conduit connected to a source of the liquid to be sprayed, the conduit being at right angles to the bore axis. An outlet nozzle from the conduit is positioned on the axis of the central bore and has its exit plane upstream of the exit plane of the bore so that atomization of the liquid will take place within the central bore between the two exit planes. A pair of shaping nozzles are connected to secondary bores that in turn communicate with the manifold. The shaping nozzles are directed orthogonally to the central bore axis as well as to the inlet conduit and are located downstream of the exit plane of the central bore. The jets issuing from the shaping nozzles shape the cone-shaped spray into a generally fan-shaped configuration. Because the shaping jets are always at the same pressure as the atomization air the dispersion of the droplets exiting the nozzle will be consistent and the spray pattern will be constant over the operating pressure range of the apparatus, thereby avoiding the problems of the prior art.
Broadly speaking, therefore, the present invention may be considered as providing a device for atomizing a liquid at low pressures comprising:
a nozzle body adapted for mounting to a manifold supplied with pressurized air;
a central bore in the nozzle body communicating at one end with the manifold and extending in a downstream direction to an exit plane at the other end;
an inlet conduit for the liquid, the conduit extending through the nozzle body into the bore at right angles thereto upstream of the exit plane, the inlet conduit being adapted for connection to a source of the liquid to be sprayed;
an outlet nozzle for the liquid, the outlet nozzle being aligned with the axis, extending downstream from the inlet conduit, and terminating at an exit plane located upstream of the central bore exit plane; and
a pair of diametrically opposed shaping nozzles positioned downstream of the central bore exit plane and extending orthogonally to the central bore axis and to the inlet conduit, each shaping nozzle being connected to a secondary bore in the nozzle body, each secondary bore communicating the shaping nozzle with the manifold;
whereby liquid fed under pressure to the inlet conduit exits the outlet nozzle and is atomized between the exit planes of the outlet nozzle and the central bore as it is mixed with air flowing along the central bore, air exiting the opposed shaping nozzles serving to shape the atomized liquid spray into a flattened fan shape.
FIG. 1 shows schematically a particular application for the present invention.
FIG. 2 shows in partial section a spray boom having atomizing nozzles of the present invention incorporated therein.
FIG. 3 is a somewhat enlarged front end view of the atomizing nozzle of the present invention.
FIG. 4 is a cross-section on the line 4--4 of FIG. 3.
FIG. 5 is a cross-section on the line 5--5 of FIG. 3.
FIG. 6 is a cross-section similar to that of FIG. 4 but with a mounting extension incorporated into the nozzle body.
FIG. 1 shows generally an application for the atomizing nozzle of the present invention. A growing crop C is illustrated, the crop including a plurality of plants P having leaves L. An agricultural spray apparatus 10 includes an elongated boom member 12 supported along its length by wheeled struts 14. The boom member 12 might be towed behind a tractor (not shown) or it might be part of a permanent installation (also not shown), adapted for example to move in a circular path about a central hub. The boom member 12, as seen in FIG. 2, is hollow, so as to define a manifold, and is connected, as at one end via conduit 18, to an adjustable source of pressurized air such as the centrifugal fan 16. Preferably, the fan 16 will provide a steady flow of pressurized air at a pressure of between about 10 in. and 30 in. of water column. In comparison to some prior art agricultural sprayers this may be considered to be a low pressure sprayer.
With reference to both FIGS. 1 and 2 it will be seen that the apparatus 10 also includes a source of liquid to be sprayed onto the crop, the source including a liquid container 20 provided with a pump 22 and a conduit 24 leading to a supply pipe 26 secured to the exterior of the boom member 12. The supply pipe 26 has a plurality of tees 28 spaced apart therealong, each tee being connected to a branch pipe 30 which in turn is connected to a nozzle 40 of the present invention. A plurality of the nozzles 40 is spaced apart along the length of the boom member 12 as seen in FIGS. 1 and 2.
The atomizing nozzle 40 of the present invention is described in greater detail with reference to FIGS. 3 to 6. The nozzle includes a generally cylindrical nozzle body 42 formed preferably from a resilient material such as a rubber or a synthetic formulation which will be unaffected by the liquid to be sprayed. The nozzle body 42 includes a central bore 44 having a diameter D over its length, the bore communicating at one (the inner) end with the manifold-defining interior of the boom member 12 and extending through the nozzle body 42 to an exit plane 46 at the other (the outer) end thereof. At its inner end the bore is provided with a radiused convex annular surface 48 defining a smooth entranceway to the bore 44. The surface 48 is defined by a radius r with the ratio r/D being about 0.25 and the surface 48 defined by the radius r extending over an arc of about 90°.
As shown in FIG. 4 the nozzle body 42 is provided with a pair of longitudinally spaced apart peripheral flanges 50,50 which define a narrow annular gap 52 therebetween. The nozzle body can be attached to the boom member 12 by forcing the inner flange into the interior of the boom member through an opening 54 therein so that the material of the boom member at the opening 54 is trapped in the gap 52 between the flanges 50,50. Since the boom member 12 is hollow, the manifold interior thereof is in direct communication with the central bore 44 of the nozzle body.
At the other end thereof the nozzle body receives a small diameter inlet conduit 56 which enters the body along a line at right angles to the central bore 44. The conduit 56 passes through one part of the nozzle body upstream of the exit plane 46, across the bore, and is anchored in the nozzle body on the other side of the bore. The conduit 56 has, projecting downstream therefrom, an outlet nozzle 58 which is aligned with the longitudinal axis A of the central bore 44. The exit plane 60 of the outlet nozzle 58 is also located upstream of the exit plane 46. The inlet conduit 56 is adapted to be connected to one of the branch pipes 30 that in turn is connected back to the source of liquid to be sprayed. Thus, the liquid to be sprayed will be supplied to the outlet nozzle 58 so that it will be forced into the central bore 44 in the region defined between the exit plane 60 and the exit plane 46.
On the outer face 62 of the nozzle body 42 there is provided a pair of diametrically opposed extensions or bosses 64, each having a shaping nozzle 66 in the form of a small diameter bore therein. The nozzles 66 are aligned with each other and extend orthogonally to both the axis of the central bore 44 and the inlet conduit 56. The end face of each extension is substantially tangential to the periphery of the central bore 44 and the nozzles 66 are positioned in the extensions so that the adjacent portion of the interior surface thereof is generally in the exit plane 46. Each shaping nozzle 66 is, in turn, connected to a longitudinally extending secondary bore 68 that communicates the shaping nozzle with the manifold interior of the boom member 12. Thus, each shaping nozzle will be supplied with air at the same pressure as the air that is supplied to the central bore 44. The secondary bores 68 are preferably parallel to the central bore 44 but it is not essential that they be so oriented.
In its preferred form the nozzle body 42 has an extension 70 at the inner end thereof, the extension carrying the peripheral flanges 50,50 that enable the nozzle body to be connected to the boom member 12. The extension 70 includes a tapered internal bore 72, with the taper being in the vicinity of 14°. As can be seen in FIG. 6 the tapered bore 72 terminates at the entranceway defined by the surface 48 such that the convex surface is exposed to incoming air from the tapered bore 72.
It has been determined that optimum spray conditions are achieved if the dimensions and layout of the nozzle body meet certain criteria, including the one pertaining to the entranceway surface 48 as indicated hereinabove. In the definitions below the following dimensions are utilized:
D=diameter of the central bore 44;
L=length of the central bore 44;
x=distance of exit plane 60 upstream of exit plane 46;
l=distance of axis of conduit 56 upstream of exit plane 60;
do =outside diameter of conduit 56;
di =internal diameter of conduit 56;
ds =internal diameter of shaping nozzle 66;
Vr =relative velocity between the air and the liquid;
Wea =aerodynamic Weber number.
The aerodynamic Weber number is used to establish the criteria for interaction of the liquid with the air stream to ensure "prompt" atomization in the central bore 44. The aerodynamic Weber number (Wea) dictates the conditions for atomization and is directly related to the size of droplets produced. The Wea is defined with the characteristic dimension parameter as in:
Wea =(Vr ρa di)/σl
where Vr and di are as defined above, ρa is the air density and σl is the liquid surface tension.
In order to achieve optimum spray conditions and performance it is recommended that the criteria hereinbelow be met. If they are not met the present invention will still be operable but it will not provide its best performance. Thus it is recommended that:
(1) L/D be about 3 so as to achieve an air velocity within central bore 44 of about 180 ft/sec to about 300 ft/sec at the operating pressure of about 10 in. to about 30 in. of water column;
(2) x/D be about 0.25;
(3) l/do be about 1.9 or greater;
(4) di be selected to provide a discharge velocity for the liquid at the exit plane 60 of about 3 ft/sec to about 40 ft/sec;
(5) ds be selected to provide a ratio of mass flow of shaping air to mass flow of air in bore 44 of about 24% to about 30%;
(6) Wea is at least 50, and may be as high as 175, so as to produce liquid droplets in the size range suitable for a variety of agricultural spray applications. Vr is therefore typically in the range of about 145 to 280 ft/sec.
Excellent results have been achieved with a prototype nozzle having the following dimensions: L=1.750 in., D=0.578 in., x=0.150 in., l=0.140 in., do =0.072 in., di =0.053 in., and ds =0.257 in.
The present invention provides a uniform spray pattern with consistent, controlled droplet size distribution within the atomized spray itself. As seen in FIG. 1 there will be overlap of the sprays from adjacent nozzles 40 at a distance below the boom member 12 of about 15 to 18 inches and the boom can be set in order to take advantage of that fact. Furthermore, the air exiting the nozzles will have sufficient force and turbulence to cause the leaves of the plants being sprayed to shake, bounce around and turn over so that the liquid can be sprayed over the complete leaf, including the underside thereof.
The FIG. 1 boom configuration assumes that the nozzles 40 are oriented so that the fan-shaped sprays overlap and are generally in a common plane. If the nozzles are rotated slightly on their central axes then the sprays will be angled relative to the boom member, while being generally parallel to each other. This orientation would provide more overlap when the boom member is moving but little or no overlap when the boom member is stationary.
The droplet size distribution achieved by the nozzle configuration of this invention remains generally constant even though the pressure within the manifold of the boom member 12 may vary, intentionally or otherwise. The droplet distribution can be shaped by the shaping nozzles 60. The combination of liquid delivery in a well-controlled internal mix environment, defined by the central bore 44, provides a prompt breakup of the liquid downstream of the outlet nozzle 58 that results in the tightly controlled droplet size distribution which can be tailored to suit the particular spray application, by choosing a nozzle having the appropriately dimensioned central bore, inlet conduit, outlet nozzle and shaping nozzle combination. Scaling of the nozzle is possible with desired and predictable spray results if the aerodynamic Weber number is maintained within the range indicated above. The configuration of the shaping nozzles and the central bore provides an environment where the droplet size distribution produced in the zone between the exit planes is not substantially affected by later aerodynamic shaping.
The foregoing has described the preferred configurations for the present invention. It is clear, however, that a skilled person could effect revisions to the present invention to suit particular applications without departing from the spirit of the invention. The protection to be afforded this invention therefore is to be determined from the claims appended hereto.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3164324 *||May 17, 1963||Jan 5, 1965||Kiekens Wervelwind Holland Kie||Spraying vehicle|
|US3252656 *||Nov 20, 1963||May 24, 1966||Fmc Corp||Spray discharge head|
|US3472454 *||Oct 26, 1967||Oct 14, 1969||Subscription Television Inc||Low volume sprayer system|
|US3625426 *||Apr 7, 1970||Dec 7, 1971||Swanson Ely||Agricultural spraying apparatus|
|US4349153 *||Jul 29, 1980||Sep 14, 1982||Champion Spark Plug Company||Spray nozzle|
|US4504014 *||Jan 31, 1983||Mar 12, 1985||D & W Industries, Inc.||Device for atomizing a liquid|
|US4673132 *||Mar 29, 1982||Jun 16, 1987||Canadian Patents And Development Limited||Spraying apparatus|
|US4927080 *||Jan 23, 1989||May 22, 1990||Hartvig Jensen & Co. A/S||Field spraying device|
|US5102051 *||Jan 26, 1989||Apr 7, 1992||Itw Limited||Spray gun|
|US5152460 *||Apr 8, 1991||Oct 6, 1992||Thomas Barty||Spray gun nozzle head|
|US5165605 *||Mar 30, 1990||Nov 24, 1992||Iwata Air Compressor Mfg. Co., Ltd.||Low pressure air atomizing spray gun|
|US5176322 *||Jun 26, 1991||Jan 5, 1993||Sartor Giuseppe M||Crop-spraying apparatus|
|US5402945 *||Jan 22, 1993||Apr 4, 1995||Gervan Company International||Method for spraying plants and apparatus for its practice|
|CA1238020A *||Jan 5, 1984||Jun 14, 1988||First National Bank In Sioux F||Device for atomizing a liquid|
|FR915224A *||Title not available|
|FR2079514A5 *||Title not available|
|GB2129711A *||Title not available|
|WO1987000078A1 *||Jun 23, 1986||Jan 15, 1987||Danfoil Aps||Atomizer|
|WO1987001909A1 *||Sep 29, 1986||Apr 9, 1987||Homburg Machinehandel||Device for spraying a liquid on a crop|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US6116516 *||Nov 13, 1998||Sep 12, 2000||Universidad De Sevilla||Stabilized capillary microjet and devices and methods for producing same|
|US6554202||May 10, 2002||Apr 29, 2003||Universidad De Sevilla||Fuel injection nozzle and method of use|
|US6595202||Sep 30, 2002||Jul 22, 2003||Universidad De Sevilla||Device and method for creating aerosols for drug delivery|
|US7959089||May 15, 2009||Jun 14, 2011||Kamterter Ii, L.L.C.||Systems for the control and use of fluids and particles|
|US8235258||Jun 3, 2011||Aug 7, 2012||Kamterter Ii, L.L.C.||Systems for the control and use of fluids and particles|
|US8288320||Oct 4, 2007||Oct 16, 2012||Oms Investments, Inc.||Methods for preparing granular weed control products having improved distribution of agriculturally active ingredients coated thereon|
|US8308075||Nov 13, 2012||Kamterter Products, Llc||Systems for the control and use of fluids and particles|
|US8707989 *||Sep 2, 2010||Apr 29, 2014||Illinois Tool Works Inc.||Mounting system for fluid discharge devices|
|US8960572 *||Dec 30, 2009||Feb 24, 2015||Illinois Tool Works Inc.||Air manifold having nozzles|
|US9148994||Nov 12, 2012||Oct 6, 2015||Kamterter Products, Llc||Systems for the control and use of fluids and particles|
|US9186881||Apr 27, 2009||Nov 17, 2015||Illinois Tool Works Inc.||Thermally isolated liquid supply for web moistening|
|US20090093368 *||Oct 4, 2007||Apr 9, 2009||Thompson Harold E||Methods for preparing granular weed control products having improved distribution of agriculturally active ingredients coated thereon|
|US20100163653 *||Dec 30, 2009||Jul 1, 2010||Illinois Tool Works Inc.||Air manifold having nozzles|
|US20100224122 *||Apr 27, 2009||Sep 9, 2010||Illinois Tool Works Inc.||Low pressure regulation for web moistening systems|
|US20110048557 *||Sep 2, 2010||Mar 3, 2011||Illinois Tool Works Inc.||Mounting system for fluid discharge devices|
|EP2377406A1||Apr 18, 2006||Oct 19, 2011||Kamterter Products, LLC||Apparatus for encapsulating materials|
|EP2381019A1||Apr 18, 2006||Oct 26, 2011||Kamterter Products, LLC||Method of forming chitosan formable material|
|EP2384608A2||Apr 18, 2006||Nov 9, 2011||Kamterter Products, LLC||Method for formulating a seed suspension material|
|EP2384748A2||Apr 18, 2006||Nov 9, 2011||Kamterter Products, LLC||Method of forming fibers|
|WO2009046312A1 *||Oct 3, 2008||Apr 9, 2009||Oms Investments Inc||Methods for preparing granular weed control products having improved distribution of agriculturally active ingredients coated thereon|
|U.S. Classification||239/433, 239/DIG.7, 239/434, 239/547|
|International Classification||B05B7/04, B05B7/08, B05B7/00|
|Cooperative Classification||Y10S239/07, B05B7/0075, B05B7/045, B05B7/0815|
|European Classification||B05B7/04C3A, B05B7/08A1|
|Jun 5, 1995||AS||Assignment|
Owner name: NATIONAL RESEARCH COUNCIL OF CANADA, CANADA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:JONASSON, KEVIN A.;MCCRACKEN, THOMAS W.;BENNETT, ADAM J.;REEL/FRAME:007665/0843
Effective date: 19950602
|May 22, 2001||REMI||Maintenance fee reminder mailed|
|Aug 22, 2001||AS||Assignment|
|Aug 22, 2001||FPAY||Fee payment|
Year of fee payment: 4
|Aug 22, 2001||SULP||Surcharge for late payment|
|Aug 11, 2005||SULP||Surcharge for late payment|
Year of fee payment: 7
|Aug 11, 2005||FPAY||Fee payment|
Year of fee payment: 8
|Sep 3, 2007||AS||Assignment|
Owner name: MILLER-ST. NAZIANZ, INC., WISCONSIN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SPRAY-AIR TECHNOLOGIES LTD.;REEL/FRAME:019773/0565
Effective date: 20070131
|Mar 8, 2009||FPAY||Fee payment|
Year of fee payment: 12
|Nov 23, 2010||AS||Assignment|
Owner name: WELLS FARGO BANK, NATIONAL ASSOCIATION, WISCONSIN
Free format text: SECURITY AGREEMENT;ASSIGNOR:MILLER - ST. NAZIANZ, INC.;REEL/FRAME:025412/0665
Effective date: 20101029
|Dec 7, 2012||AS||Assignment|
Owner name: MILLER-ST. NAZIANZ, INC., WISCONSIN
Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:WELLS FARGO BANK, NATIONAL ASSOCIATION;REEL/FRAME:029429/0166
Effective date: 20121205
|Dec 23, 2014||AS||Assignment|
Owner name: CNH INDUSTRIAL AMERICA LLC, PENNSYLVANIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MILLER ST. NAZIANZ, INC.;REEL/FRAME:034576/0934
Effective date: 20141223